Thin-walled battery for portable electronic equipment

ABSTRACT

The present invention provides a thin battery, comprising a metal case, a battery core formed by laminating and wrapping an anode, a septum and a cathode, an anode conductive terminal and a cathode conductive terminal, characterized in that: said metal case is made of a quadratic shallow trough having five thin-walls and a top cover welded on the trough; the shallow trough has outlets for the electrodes.

FIELD OF THE INVENTION

The present invention relates to a thin battery, particularly to a thinbattery suitable for portable electronic equipments.

BACKGROUND OF THE INVENTION

In resent years, for meeting the requirements of developing electronicequipment, especially communication equipments such as mobilephone, athinner battery used as one of the necessary components of the saidequipments is required. The conventional metal case used as the sealingcase of the battery core is thicker and occupies more space. In order toovercome the above-mentioned defects, a composite material of metal foiland plastic film or thermos-fused polymer film is adopted. However, thestrength of this composite material is not sufficient, and it is easierto deform which is harmful to the electronic equipments. Therefore, theapplication field of this composite material is limited It is well-knownin the art that, during the use of some common batteries with a liquidelectrolyte, such as nickel-cadmium battery, metal hydride-nickelbattery, lithium ion battery and lithium battery, especially under theovercharged state, the production of gases is unavoidable. In view ofsafety, it is necessary to select a battery case having bettermechanical strength. In consideration of safety, the metal caseundoubtedly is a good choice. However, the thinness of the metal case isbound to bring many difficulties in manufacture process, includingwelding and sealing. For examples, the trough body of the battery isusually deeper which makes it difficult to put the battery core into thetrough or the active substance on the electrode will be scraped duringthe process of putting the battery core into the trough. Moreover, thesmaller area of the cover of the battery also increases the difficultyof laser welding. Moreover, the explosion-protective device mounted inthe trough of the battery is usually a thin whittling concave trough.Because of the nature of metal and poor uniformity of thickness afterwhittling, the explosion-protective performance of the battery isgenerally unsatisfying. Having conducted studies for a long time, theinventors of the present invention eventually improved the battery caseand the terminal sealing system to overcome the above-mentioned defectssuccessfully, thereby completes the present invention.

OBJECT OF THE INVENTION

The object of the present invention is to provide a thin battery whichis easy to be welded and assembled and having good sealing performance.

SUMMARY OF THE INVENTION

The present invention provides a thin battery comprising a metal case, abattery core formed by laminating and wrapping an anode, a septum and acathode together, an anode conductive terminal and a cathode conductiveterminal, characterized in that said metal case is made up of a quadrateor rectangular shallow trough having five thin-walls and a thin coverwelded on the top of the trough; said shallow trough has outlets for theelectrodes. According to the thin battery of the present invention, thetrough is shallower and its opening is bigger, the battery core is easyto be put into the trough of the thin battery and the cover is easy tobe welded.

According to the thin battery of the present invention, characterized inthat an outlet for the conductive terminal is provided on the narrowside wall of the metal case, the outlet is sealed by a rubber stopper;one conductive terminal is guided out from the outlet passing throughthe rubber stopper, and the other conductive terminal is welded on themetal case and is guided out.

According to the thin battery of the present invention, characterized inthat two outlets for the conductive terminals are provided on the narrowside wall of the metal case, the outlets are sealed by rubber stoppers;the anode conductive terminal and the cathode conductive terminal areguided out from the two outlets passing through the rubber stoppersrespectively.

According to the thin battery of the present invention, said sealingrubber stopper of the metal case is a wedge-shaped stopper with a neck,which has the size corresponding to that of the outlet.

According to the thin battery of the present invention, the part of themetal case corresponding to the outlet is mechanically pressurized tomake it deformed so that the metal case is tightly connected with therubber stopper and the conductive terminals to form a sealed structure.

According to the thin battery of the present invention, said material ofthe sealing rubber stopper is selected from the group consisting ofbutadiene styrene rubber, neoprene rubber, butyl rubber, polyacrylaterubber and butadiene-acrylonitrile rubber.

According to the second aspect of the present invention, it is provideda thin battery comprising a metal case, a battery core formed bylaminating and wrapping an anode, a septum and a cathode together, ananode conductive terminal and a cathode conductive terminal,characterized in that said metal case is made of a quadrate orrectangular shallow trough having five thin-walls and a thin coverwelded on the top of the trough; at least one inwards recess with anaperture is provided on the bottom wall and along one of the side walls;a complex sealing element is provided to seal the recess and to connectwith the conductive terminals.

According to the thin battery of the present invention, the complexsealing element includes an isolation element covering and clipping thebottom edge of the recess, and a metal element imbedded in the aperture.

According to the thin battery of the present invention, said isolationelement is made of a plastic or rubber material and covers the bottomedge of the recess by means of, for example, compression casting so asto integrate it with the recess.

According to the thin battery of the present invention, said metalelement is in the shape of rivet, and its shape and size iscorresponding to those of the aperture of the recess and its height isslightly higher than the depth of the aperture, and when the metalelement is imbedded, it is compressed longitudinally to expandhorizontally, so that the metal element, the isolation element and theshallow trough are combined to form a good sealing system.

According to the thin battery of the present invention, the metal caseis made of the materials selected from the group consisting of aluminum,stainless steel and nickel-plated steel.

According to the thin battery of the present invention, the bottom walland the top cover of the aluminum case are provided with a reinforcingrib to increase the strength, said reinforcing rib is a concave-convexgrove formed by mechanically stamping said trough and cover.

According to the thin battery of the present invention, said metal casehas a shallow trough with four side walls having smaller surfaces and abottom wall having larger surface. Therefore, it is easy to bemanufactured. By adopting a cover having a size corresponding to that ofthe bottom wall of the trough to seal the side walls, the welding andassembling of the battery become easier. On one of the narrow sidewalls, said metal case has outlets for conductive terminals sealed bywedge-shaped rubber stoppers with a neck. The conductive terminals areguided out from the outlets passing through the rubber stoppers. Theparts of said metal case corresponding to said outlets are mechanicallypressured to make them deformed and thus to make the metal case, therubber stoppers and the conductive terminals form tough sealingstructure with good sealing performance. As an alternatively sealingmethod for the conductive terminals, said metal case has at least onesmall inwards recess with an aperture on the bottom wall and along oneof the narrow side walls, a complex sealing element is provided to sealthe recess and to connect with the conductive terminals to form anintegrative sealing structure with the good sealing performance. Insummary, the thin battery of the present invention solves the problemsof the prior manufacture techniques including the problems for weldingand sealing during the process for manufacturing a thin battery. Thethin battery of the present invention has good sealing performance andmeets the requirements of developing electronic equipments, especiallycommunication equipments such as cell phones.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the structure of the first embodiment of the thin batteryof the present invention.

FIG. 2 shows the structure of the terminal sealing in the firstembodiment of the thin battery of the present invention.

FIG. 3 shows the section view of the terminal sealing stopper in thefirst embodiment of the thin battery of the present invention.

FIG. 4 shows the structure of the second embodiment of the thin batteryof the present invention.

FIG. 5 shows the section view of the recess on the battery case as shownin FIG. 4.

FIG. 6 shows the section view of the recess of the battery case as shownin FIG. 5 clipped by an isolation element.

FIG. 7 shows the section view of the integrative structure of the recessof the battery case as shown in FIG. 4 clipping by a complex sealingelement.

DETAILED DESCRIPTION

The present invention will be described in combination with the drawingshereinafter. It should be understood that the embodiments do not limitthe scope of protection of the claims of the present invention.

FIG. 1 shows the structure of the first embodiment of the thin batteryof the present invention. As shown in FIG. 1, the thin battery of thepresent invention comprises a metal case 1, a battery core 6 formed bylaminating and wrapping an anode, a septum and a cathode together, ananode conductive terminal 2 and a cathode conductive terminal 2′.Wherein, the metal case 1 is made of a quadrate or rectangular shallowtrough and a top covering 4 welded on the trough. On one of the narrowside walls of the shallow trough of the metal case 1, there are twooutlets for guiding out the anode conductive terminal 2 and the cathodeconductive terminal 2′ respectively. The outlets are sealed by butadienestyrene rubber stoppers 3 as shown in FIG. 3 by means of the methodshown in FIG. 2. The battery core 6 is a MH/NI battery core manufacturedby the technique disclosed in the Chinese patent application No.CN1076313A. FIG. 2 shows not only the sealing method of the outlets, butalso the situation of the battery case used as the cathode conductiveterminal 2′. As shown in FIG. 2, an anode conductive terminal 2 isguided out from the outlet passing through a butadiene styrene rubberstoppers 3, while the other conductive terminal is welded on the innersurface of the top cover 4. The top cover 4 is welded on the shallowtrough of the metal case 1, the part of the metal case 1 correspondingto the outlet is mechanically pressurized to deform, and to make themetal case 1, the rubber stoppers 3 and the conductive terminals 2 forma tough sealing structure. Fifty MH/NI batteries having the saidstructure are manufactured and are conducted the charging anddischarging circle for 10 times. No liquid leaking is found among thesebatteries.

According to the present invention, the shallow trough of the metal case1 can also have two outlets for the conductive terminals on one of thenarrow side walls (As shown in FIG. 1). Fifty lithium-ion batteries,whose battery cores are lithium-ion battery core with a liquidelectrolyte made by means of the technique as disclosed in the Chinesepatent application No. CN1186335A, are manufactured according to themethod mentioned above. These lithium-ion batteries are conducted thecharging and discharging circle for 10 times. One battery has theproblem of liquid leaking among these batteries.

The results of the above embodiments show that the present inventionadopts rubber stopper sealing to replace conventional sealing and makesthe metal case, the rubber stopper and the conductive terminals form atough sealing structure so as to solve the problems of welding andsealing existed in the prior manufacture techniques for making a thinbattery having a thinner metal case.

FIG. 4 shows the structure of the second embodiment of the thin batteryof the present invention. In this embodiment, the same elements areindicated by the same labels as used in the first embodiment, but theselabels are not shown in FIG. 4. As shown in FIG. 4 and FIG. 1, the thinbattery of the present invention comprises a metal case 1, a batterycore 6 usually used in this field, such as a battery core 6 formed bylaminating and wrapping an anode, a septum and a cathode together, ananode conductive terminal and a cathode conductive terminal. Wherein,the metal case 1 is a quadrate or rectangular shallow trough of aluminumand an aluminum top cover 4 welded on the trough. As shown in FIG. 4 toFIG. 7, the shallow trough of the metal case 1 has a small recess 7 withan aperture 7A provided on the bottom wall and along one of the narrowside walls. A complex sealing element (8 a+8 b) seals the recess 7 andthe aperture 7A. The complex sealing element includes an isolationelement 8 b clipping the edge of the aperture as well as the recess, anda metal element 8 a imbedded in the aperture. The isolation elementclips the bottom wall of the recess by means of compression casting PPSto integrate it with the recess. The shape and size of the metalelement, which is in the shape of nail, match with those of the apertureof the isolation element and a little bit higher, and is compressedlongitudinally to expand horizontally, so that the metal element and theisolation element and the shallow trough form a good sealing system. Thebattery core is a lithium ion battery core with a liquid electrolytemanufactured by means of the technique disclosed in the Chinese patentapplication No. CN186335A. A terminal is guided out by being welded onthe lower end of the metal element 8 a, while the other terminal iswelted on the inner surface of the top cover 4. The top cover 4 iswelded on the shallow trough of the metal case 1. The liquid electrolyteis injected into the battery via a liquid injection opening and theliquid injection opening is sealed by dot welding after the liquidelectrolyte injection. In this way, fifty lithium-ion batteries aremanufactured. These lithium-ion batteries are conducted the charging anddischarging circle for 10 times. No liquid leaking is found among thesebatteries.

The battery case shown in FIG. 4 is manufactured by using aluminum asthe metal material. The metal case 1 has two recesses 7 with an aperture7A provided on the bottom wall and along one of the narrow side walls.The recesses 7 are sealed by complex sealing elements respectively. Thebattery core is a MH/NI battery core made by means of the techniquedisclosed in the Chinese patent application No. CN1076313A. The topcovering 4 is welded on the shallow trough of the metal case 1. Theliquid electrolyte is injected into the battery via a liquid injectionopening and the liquid injection opening is sealed by dot welding afterthe liquid electrolyte injection. In this way, fifty MH/NI batteries aremanufactured. These MH/NI batteries are conducted the charging anddischarging circle for 10 times. One battery has the problem of liquidleaking among these batteries.

The results of the above-mentioned embodiments show that, according tothe thin battery of the present invention, the shallow trough of themetal case has recesses with an aperture provided on the bottom wall andalong one of the narrow side walls, and complex sealing elements insteadof conventional sealing elements are used to make the metal element, theisolation element and the shallow trough form a good sealing system withgood sealing performance so as to solve the problems existed in theprior manufacture method welding and sealing for making thin battery.

INDUSTRIAL APPLICABILITY

The thin battery of the present invention can be widely used in avariety of electronic equipments requiring thin batteries, especiallycommunication equipments, such as mobile phones.

1. A thin battery comprising a metal case; a battery core formed bylaminating and wrapping an anode, a septum and a cathode together; ananode conductive terminal; and a cathode conductive terminal, whereinsaid metal case is made of a rectangular shallow trough and a thin coverwelded on top of the rectangular shallow trough, said rectangularshallow trough having four side walls and a bottom, wherein said metalcase has an outlet on one of the four side walls, the outlet is sealedby a rubber stopper; one of the conductive terminals is guided out fromthe outlet passing through the rubber stopper, and the other conductiveterminal is welded on the metal case and conducts electricity throughthe metal case.
 2. A thin battery comprising a metal case; a batterycore formed by laminating and wrapping an anode, a septum and a cathodetogether; an anode conductive terminal; and a cathode conductiveterminal, wherein said metal case is made of a rectangular shallowtrough and a thin cover welded on top of the rectangular shallow trough,said rectangular shallow trough having four side walls and a bottom,wherein said metal case has two outlets on one of the four side walls,the outlets are sealed by rubber stoppers; the anode conductive terminaland the cathode conductive terminal are separately guided out from thetwo outlets passing through the rubber stoppers.
 3. The thin battery inaccordance with claim 1 or 2, wherein said rubber stopper is awedge-shaped stopper with a neck, which has a size corresponding to thatof the outlet.
 4. The thin battery in accordance with claim 3, wherein aportion of the metal case around the outlet is mechanically pressed sothat the metal case, the rubber stopper, and the conductive terminalsform a seal over the outlet.
 5. The thin battery in accordance withclaim 1 or 2, wherein a material of the rubber stopper is selected fromthe group consisting of butadiene styrene rubber, neoprene rubber, butylrubber, polyacrylate rubber and butadiene-acrylonitrile rubber.
 6. Athin battery comprising a metal case; a battery core formed bylaminating and wrapping an anode, a septum and a cathode together; ananode conductive terminal; and a cathode conductive terminal, whereinsaid metal case is made of a rectangular shallow trough and a thin coverwelded on top of the rectangular shallow trough, the rectangular shallowtrough having four side walls and a bottom; an inwards recess having anaperture is provided on the bottom along one of the four side walls; anda complex sealing element is provided to cover the inwards recess and toconnect one of the conductive terminals.
 7. The thin battery inaccordance with claim 6, wherein said complex sealing element includesan insulating piece covering the recess and a metal piece in aninsulating passage that is part of the insulating piece and passesthrough the aperture.
 8. The thin battery in accordance with claim 7,wherein said insulating piece is made of a plastic or rubber material.9. The thin battery in accordance with claim 7, wherein said metal pieceis in a shape of a rivet having a head portion and a body portion, theinsulating piece has an indentation around the insulating passageadapted to receive the head portion of the metal piece, and a shape anda size of the body portion of the metal piece corresponds to a shape anda size of the insulating passage, a height of the head portion of themetal piece is slightly higher than the depth of the indentation, andwhen the metal piece is pressed longitudinally the head portion of themetal piece expands horizontally, so that the metal piece, theinsulating piece and the rectangular shallow trough form a good sealingsystem over the aperture.
 10. The thin battery in accordance with claim1, 6 or 2, wherein the metal case is made of a material selected fromthe group consisting of aluminum, stainless steel, and nickel-platedsteel.
 11. The thin battery in accordance with claim 10, wherein thematerial is aluminum and the bottom of the metal case and the cover ofthe metal case are provided with at least one reinforcing rib.